Bench assembly and bi-directional optical transceiver constructed therewith

ABSTRACT

Disclosed is a method that includes providing an optical fiber, providing a bench that supports a chip-level optical transceiver, placing the bench in front of the optical fiber, activating the chip-level optical transceiver, and tilting the bench until the chip-level optical transceiver is aligned with the optical fiber and an optical signal is achieved.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. ProvisionalApplication Serial No. 60/412,256, filed Sep. 23, 2002.

FIELD OF THE INVENTION

[0002] This invention relates to optical transceivers and, moreparticularly, to packaged optical transceivers.

BACKGROUND OF THE INVENTION

[0003] Optical fibers are useful in high-speed data transmissionsystems. These high-speed systems can include an optical fiber opticallycoupled to a module which includes a light emitting or light detectingdevice. A module with a light emitting device is typically referred toas a transmitter module wherein an electrical signal is converted to alight signal which is emitted by the light emitting device and isincident to the optical fiber. A module with a light detecting device istypically referred to as a receiver module wherein an optical signal isconverted to an electrical signal.

[0004] It is important to minimize the cost of the components includedin fiber optic systems. In the prior art, the high cost of transceiversbuilt with existing technology makes it cost prohibitive to undertakeinstallation of extensive fiber networks with individual connections.Thus, it is highly desirable to provide a cost effective optical packagewhich is capable of transmitting and receiving data in a fiber to a homenetwork.

SUMMARY OF THE INVENTION

[0005] The above problems and others are at least partially solved andthe above purposes and others realized in a preferred apparatusembodiment including a header having a surface defining a substantiallyhorizontal plane, and a chip-level optical transceiver carried by abench disposed in a tilted state for aligning the chip-level opticaltransceiver with an optical fiber. In a particular embodiment, anoptical fiber is aligned with the chip-level optical transceiver.Preferably, a package secures and contains the optical fiber, the bench,and the chip-level optical transceiver carried by the bench. The packageincludes a support structure securing the fiber, and a header coupled tothe support structure, in which the bench is carried by the header infront of the optical fiber. Preferably, the package hermetically sealsthe bench and the chip-level optical transceiver carried thereby. Thechip-level optical transceiver includes a light emitting device, havingan output, for emitting a first wavelength of light along a firstoptical path, a first photodiode for controlling the output of the lightemitting device, a second photodiode having an active region, a lens forreceiving the first wavelength of light along the first optical pathfrom the light emitting device and collimating the first wavelength oflight to the second photodiode along the first optical path, and thesecond photodiode for reflecting the first wavelength of light along thefirst optical path into the optical fiber along a second optical path.The optical fiber is operative for transmitting a second wavelength oflight to the second photodiode along the second optical path. The secondphotodiode adapted and arranged to permit the second wavelength of lightto pass therethrough to the active region thereof for conversion into anelectrical signal. The first wavelength of light is different from thesecond wavelength of light, and the first optical path is coincident tothe second optical path.

[0006] In an optical fiber and a header mounted adjacent the opticalfiber, the invention also provides apparatus therein consisting of achip-level optical transceiver supported by a bench carried by theheader in a tilted state aligning the chip-level optical transceivercomponents with the optical fiber. Preferably, a package secures andcontains the optical fiber, the bench, and the chip-level opticaltransceiver carried by the bench. The package includes a supportstructure securing the fiber, and a header coupled to the supportstructure, in which the bench is carried by the header in front of theoptical fiber. Preferably, the package hermetically seals the bench andthe chip-level optical transceiver carried thereby. The chip-leveloptical transceiver includes a light emitting device, having an output,for emitting a first wavelength of light along a first optical path, afirst photodiode for controlling the output of the light emittingdevice, a second photodiode having an active region, a lens forreceiving the first wavelength of light along the first optical pathfrom the light emitting device and collimating the first wavelength oflight to the second photodiode along the first optical path, and thesecond photodiode for reflecting the first wavelength of light along thefirst optical path into the optical fiber along a second optical path.The optical fiber is operative for transmitting a second wavelength oflight to the second photodiode along the second optical path. The secondphotodiode adapted and arranged to permit the second wavelength of lightto pass therethrough to the active region thereof for conversion into anelectrical signal. The first wavelength of light is different from thesecond wavelength of light, and the first optical path is coincident tothe second optical path.

[0007] In accordance with the principle of the invention, furtherprovided is a method comprising steps of providing an optical fiber,providing a bench that supports a chip-level optical transceiver,placing the bench in front of the optical fiber, activating thechip-level optical transceiver, and tilting the bench until thechip-level optical transceiver is aligned with the optical fiber and anoptical signal is achieved. Further to the method is the step ofmounting the optical fiber, the bench, and the chip-level opticaltransceiver carried by the bench in a package. The package includes asupport structure securing the fiber, and a header coupled to thesupport structure, in which the bench is carried by the header in frontof the optical fiber. The chip-level optical transceiver includes alight emitting device, having an output, for emitting a first wavelengthof light along a first optical path, a first photodiode for controllingthe output of the light emitting device, a second photodiode having anactive region, a lens for receiving the first wavelength of light alongthe first optical path from the light emitting device and collimatingthe first wavelength of light to the second photodiode along the firstoptical path, and the second photodiode for reflecting the firstwavelength of light along the first optical path into the optical fiberalong a second optical path.

[0008] In accordance with the foregoing summary of preferredembodiments, and the ensuing specification, which are intended to betaken together, the invention also contemplates associated apparatus andmethod embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Referring to the drawings:

[0010]FIG. 1 is a simplified, vertical sectional view of an integratedtransceiver package incorporating a tilted bench assembly supportingchip-level optical transceiver components, in accordance with theprinciple of the invention; and

[0011]FIG. 2 is a simplified, vertical sectional view of the tiltedbench assembly of FIG. 1 carried by a header and disposed in opticalalignment with an optical fiber.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0012] An integrated bi-directional transceiver is disclosed, whichincludes a package that incorporates a header. An optical fiber extendsinto the package, and is secured thereby adjacent the header. Achip-level optical transceiver is supported by a bench carried by theheader in a tilted state aligning the chip-level optical transceivercomponents with the optical fiber. Also disclosed in this specificationis a header having a surface defining a substantially horizontal plane,and a chip-level optical transceiver carried by a bench disposed in atilted state for aligning the chip-level optical transceiver with anoptical fiber. In an optical fiber and a header mounted adjacent theoptical fiber, this disclosure still further provides improvementstherein including a chip-level optical transceiver supported by a benchcarried by the header in a tilted state aligning the chip-level opticaltransceiver components with the optical fiber. Further still, thisdisclosure presents a method that includes providing an optical fiber,providing a bench that supports a chip-level optical transceiver,placing the bench in front of the optical fiber, activating thechip-level optical transceiver, and tilting the bench until thechip-level optical transceiver is aligned with the optical fiber and anoptical signal is achieved.

[0013] Turning now to the drawings, in which like reference charactersindicate corresponding elements throughout the several views, attentionis first directed to FIG. 1, in which there is seen a simplified,vertical sectional view of a an integrated bi-directional transceiverpackage 100 incorporating a tilted bench assembly 105 supportingchip-level optical transceiver components, in accordance with theprinciple of the invention. The chip-level optical components carried bybench assembly 105 are considered part of bench assembly 105. Package100 incorporates a header 106, which is the underlying support for benchassembly 105. Header 106 has an inner face or surface 109 and anopposing outer face or surface 113. Surfaces 109 and 113 reside inspaced-apart, substantially parallel planes. Header 106 is fashioned ofsteel that is coated with gold plating of a predetermined thickness,although it can be constructed of another metal or combination of metalsand/or metal composites, or from a non-metallic material such asco-fired ceramic, or other material or combination of materials capableof providing support for placement of bench assembly 105 as describedbelow. Bench assembly 105 is carried by header 106, and header 106constitutes the underlying support for bench assembly 105. Header 106supports leads 112, which extend therethrough between surface 109 andsurface 113, as illustrated. Leads 112 are fashioned of conductivematerial, and provide electrical communication between the transceivercomponents of package 100 and external electrical components.Preferably, leads 112 are gold plated and are separated from header 106by insulators, such as glass insulators. In a preferred embodiment,package 100 incorporates approximately eight leads. However, less ormore can be used, if desired, including even one lead.

[0014] Header 106 supports a recess 110, which is formed therein throughsurface 109. In accordance with the invention, recess 100 defines a ramp110A, which is oriented at an angle θ (FIG. 2) relative to surface 109.Bench assembly 105 is held by recess 110, and is disposed against ramp110A so as to reside in a tilted state, thus aligning its chip-leveloptical transceiver components in a tilted state. Ramp 110A is thusformed to receive and hold bench assembly 105, which carries transceivercomponents operable for emitting a wavelength of light λ₁ along anoptical path 220. Bench assembly 105 is described in more detail belowin conjunction with FIG. 2.

[0015] In the preferred embodiment disclosed herein, package 100includes a preamplifier 107 attached to surface 109, which is coupled inelectrical communication to bench assembly 105 and lead 112.Preamplifier 107, which is an optical component, amplifies electricalsignals from bench assembly 105. Preamplifier 107 can be omitted, ifdesired.

[0016] Package 100 incorporates an attached can structure 104, whichoverlies surface 109. Can structure 104 is attached to header 106,preferably to surface 109, and cooperates with header 106 to enclosebench assembly 105 and preamplifier 107. Can structure 104 provideshermetic sealing of bench assembly 105 and preamplifier 107. Canstructure 104 defines opposing openings 114 and 115, in which opening114 is located proximate surface 109, and opening 115 is formed oppositesurface 109 and is adapted and arranged to receive therethrough anoptical fiber 101.

[0017] Bench assembly 105 is disposed in recess 110 and against ramp110A, as previously mentioned, and, in accordance with the invention, isoptically aligned with, and thus optically coupled to, fiber 101. Thetilt of bench assembly 105 as defined by angle θ, as defined by ramp110A, is in a range from approximately 5° to 40° relative to surface 109of header 106. In accordance with the invention, fiber 101 is thusoptically aligned with bench assembly 105, in which the opticalalignment is facilitated by the tilt of bench assembly 105 relative tofiber 101.

[0018] Optical fiber 101 extends into package 100, and is operative fortransmitting a wavelength of light λ₂ from a remote light source ortransmitter. Optical fiber 101 is held in place by package 100, so as tobe disposed therein, and through opening 115 of can structure 104, witha flange 103, which is part of package 100. Flange 103 is externallyattached to can 104 proximate opening 115, such as by way of a selectedadhesive or welding or solder or the like, encircles fiber 101, andsupports fiber 101, thus holding it in place. Overlying flange 103 is aferrule assembly 102, which is also part of package 100. Fiber 101passes through, and is secured by, ferrule assembly 102. Ferruleassembly 102, flange 103 and can structure 104 cooperate as a supportstructure for fiber 101, in which this defined support structure isattached to header 106. Flange 103 can be considered part of canstructure 104, if desired. Because header 106 is attached to canstructure 104, header 106 can be considered part of, or otherwise anextension of, can structure 104 and, therefore, part of or otherwise anextension of the support structure as defined herein.

[0019] Package 100 also incorporates an attached strain relief boot 108,which surrounds can structure 104, flange 103, and ferrule assembly 102,and also a portion of fiber 101 extending upwardly from ferrule assembly102. Strain relief boot 108 provides added support to package 100, andinhibits package 100 from becoming fractured or otherwise damaged as aresult of turns or thrust abuse. Strain relief boot 108 encloses canstructure 104, flange 103, ferrule assembly 102, and the portion offiber 101 extending into and through ferrule assembly 102 to within canstructure 104.

[0020] Looking to FIG. 2, bench assembly 105, which functions as atransceiver as previously mentioned, consists of a bench 205, which, inaccordance with the principle of the invention, supports chip-leveloptical transceiver components, namely, two photodiodes 201 and 204, alight emitting device 202, and a lens 203. In a further and moreparticular aspect, the chip-level optical transceiver components ofbench assembly 105 function as a chip-level optical transceiver. Bench205 is elongate, is generally rectangular in shape, and, for the purposeof orientation in connection with the ensuing discussion, has opposingends 205A and 205B, and opposing upper and lower surfaces 205C and 205D.Pockets or trenches 225, 226, and 227, which are disposed between ends205A and 205B, and are formed into bench 205 through upper surface 205C.Trench 225 is V-shaped and is disposed adjacent end 205A. Trench 227 isalso V-shaped, and is disposed adjacent end 205B. Trench 226 isgenerally V-shaped, and is disposed between trenches 225 and 226.Trenches 225, 226, and 227, are formed into bench 205, such as by way ofetching (e.g., wet or dry etching), cutting, machining, etc. Bench 205is integrally fashioned, and is constructed of silicon (Si), a lowtemperature co-fired ceramic, or a similar material or combination ofmaterials that can be etched or otherwise cut to form trenches 225, 226,and 227. Photodiode 201 is carried by trench 225, lens 203 is carried bytrench 226, photodiode 204 is carried by trench 227, and light emittingdevice 202 is attached to upper surface 205C between trenches 225 and226, and between photodiode 201 and lens 203.

[0021] Light emitting device 202 is operable for emitting light atwavelength λ₁ along an optical path 220. Preferably, light emittingdevice 202 is an edge-emitting emitting semiconductor laser. However,light emitting device 202 can be a face-emitting semiconductor laser, orother desired form of laser-emitting device. Trenches 225, 226, and 227,are aligned on optical path 220.

[0022] Photodiode 201 is held in trench 225 and rests against a majorsurface 225A of trench 225, and is positioned or otherwise aligned sothat it is able to detect light at wavelength λ₁ emitted through end 230of device 202 along optical path 220. Photodiode 201 controls the outputof light emitting device 202, and this arrangement is well known in theart. End 230 of device 202 is directed toward photodiode 201. Lens 203is held in trench 226, and is positioned to direct, e.g., collimate,light at wavelength λ₁ emitted through end 231 of device 202 tophotodiode 204. Lens 203 is preferably a ball lens, although those ofordinary skill will appreciate that other lens forms can be used.Photodiode 204 is held in trench 227 and rests against a major surface227A thereof, and is positioned or otherwise aligned so that it is ableto detect light at wavelength λ₁ from lens 203 along optical path 220.Photodiode 204 incorporates a dichroic filter 223, which, in thepreferred embodiment disclosed herein, consists of an applied dichroicmirror, although it can consist of an applied thin film of dichroicmaterial, if desired. Dichroic filter 223 defines an outer surface 222.

[0023] As previously mentioned, optical fiber 101 transmits a wavelengthof light λ₂, from a light source or transmitter, along optical path 221.Bench assembly 105 and fiber 101 are optically aligned so as to providea peak optical signal, in which optical path 220 is coincident relativeto optical path 221. Light at wavelength λ₂ from lens 203 along opticalpath 220 is directed against dichroic filter 223 of photodiode 204, andis reflected therefrom into fiber 101 along optical path 221. Light atwavelength λ₂ from optical fiber 101 along optical path 221 is alsodirected toward dichroic filter 223 of photodiode 204, and passestherethrough to an active region of photodiode 204 and is converted intoan electrical signal.

[0024] And so it is to be understood that dichroic filter 223, which isconsidered part of photodiode 204, is adapted and arranged to reflectwavelength of light λ₁ into fiber 101 along optical path 221, and topermit the wavelength of light λ₂ along optical path 221 to passtherethrough photodiode 204 to an active region thereof for conversioninto an electrical signal. In one embodiment, λ₁ can be 1310 nm and λ₂can be 1550 nm. In another embodiment, λ₁ can be 1550 nm and λ₂ can be1310 nm. It will be understood that 1310 nm and 1550 nm are wavelengthstypically used in optical fiber communication systems. However, it willbe understood that other wavelengths could be used, and that the use of1310 nm and 1550 nm in this disclosure is set forth as a matter ofexample and not by way of limitation.

[0025] Surface 222 is oriented at an angle φ relative to optical path220 by tilting bench assembly 105 at a desired angle, namely, angle θ asprovided by ramp 110A, or, in accordance with an alternate embodiment,by choosing an angle γ of surface 227A of trench 227. Hence, lightemitting device 202 and fiber 101 can be optically aligned by choosingat least one of angles θ, φ, and γ. In a preferred embodiment, opticalpaths 220 and 221 are optically aligned by disposing bench assembly 105at a desired tilt or angle as defined by angle θ, in accordance with theprinciple of the invention.

[0026] In order to align optical fiber 101 with the chip-level opticaltransceiver of bench assembly 105 in accordance with an exemplary methodof the invention, it is to be understood that optical fiber 101, andbench assembly 105 including bench 205 and the attached chip-leveloptical transceiver components, are to be provided as disclosed herein.Bench 205 is to be placed in front of optical fiber 101. The chip-leveloptical transceiver is activated so as to generate wavelength of lightλ₁ along optical path 220, and bench 205 is then tilted until thechip-level optical transceiver of bench assembly 105 is aligned withoptical fiber 101 and an optical signal is achieved.

[0027] Thus, an integrated bi-directional optical transceiver isdisclosed, which is capable of transmitting and receiving data in anoptical fiber, which can be used in a network and in other ways, namely,as a phase converter in a computer, and in other like applications. Alsodisclosed is a chip-level optical transceiver carried by a tilted benchfor aligning the chip-level optical transceiver with an optical fiber,and a method of aligning a chip-level optical transceiver with anoptical fiber. A bi-directional optical transceiver constructed inaccordance with the principle of the invention is easy to construct andinexpensive, and is capable of providing low cost and high power opticalcommunication in a fiber to a network. Because the transceiver packagedisclosed herein incorporates a bench to which chip-level opticaltransceiver components are attached, a transceiver package constructedand arranged in accordance with the principle of the invention is highlycompact, and very small, as compared to existing transceiver packages.The transceiver package disclosed herein allows bi-directionalcommunication by using a dichroic filter positioned on a photodiode. Thedichroic filter is chosen to allow the transmission of one wavelength oflight while allowing the reflection of another wavelength of light.

[0028] The present invention is described above with reference to apreferred embodiment. Those skilled in the art will recognize thatchanges and modifications may be made in the described embodimentwithout departing from the nature and scope of the present invention.Various changes and modifications to the embodiment herein chosen forpurposes of illustration will readily occur to those skilled in the art.To the extent that such modifications and variations do not depart fromthe spirit of the invention, they are intended to be included within thescope thereof.

Having fully described the invention in such clear and concise terms asto enable those skilled in the art to understand and practice the same,the invention claimed is:
 1. Apparatus comprising: a header having asurface defining a substantially horizontal plane; and a chip-leveloptical transceiver carried by a bench disposed in a tilted state foraligning the chip-level optical transceiver with an optical fiber. 2.Apparatus of claim 1, further comprising an optical fiber aligned withthe chip-level optical transceiver.
 3. Apparatus of claim 2, furthercomprising a package securing and containing the optical fiber, thebench, and the chip-level optical transceiver carried by the bench. 4.Apparatus of claim 3, wherein the package comprises: a support structuresecuring the fiber; a header coupled to the support structure; and thebench carried by the header in front of the optical fiber.
 5. Apparatusof claim 4, wherein the package hermetically seals the bench and thechip-level optical transceiver carried thereby.
 6. Apparatus of claim 5,wherein the chip-level optical transceiver comprises: a light emittingdevice, having an output, for emitting a first wavelength of light alonga first optical path; a first photodiode for controlling the output ofthe light emitting device; a second photodiode having an active region;a lens for receiving the first wavelength of light along the firstoptical path from the light emitting device and collimating the firstwavelength of light to the second photodiode along the first opticalpath; and the second photodiode for reflecting the first wavelength oflight along the first optical path into the optical fiber along a secondoptical path.
 7. Apparatus of claim 6, further comprising: the opticalfiber for transmitting a second wavelength of light to the secondphotodiode along the second optical path; and the second photodiodeadapted and arranged to permit the second wavelength of light to passtherethrough to the active region thereof for conversion into anelectrical signal.
 8. Apparatus of claim 7, wherein the first wavelengthof light is different from the second wavelength of light.
 9. In anoptical fiber and a header mounted adjacent the optical fiber, apparatustherein comprising a chip-level optical transceiver supported by a benchcarried by the header in a tilted state aligning the chip-level opticaltransceiver components with the optical fiber.
 10. Apparatus of claim 9,further comprising a package securing and containing the optical fiber,the bench, and the chip-level optical transceiver carried by the bench.11. Apparatus of claim 10, wherein the package comprises: a supportstructure securing the fiber; a header coupled to the support structure;and the bench carried by the header in front of the optical fiber. 12.Apparatus of claim 11, wherein the package hermetically seals the benchand the chip-level optical transceiver carried thereby.
 13. Apparatus ofclaim 12, wherein the chip-level optical transceiver comprises: a lightemitting device, having an output, for emitting a first wavelength oflight along a first optical path; a first photodiode for controlling theoutput of the light emitting device; a second photodiode having anactive region; a lens for receiving the first wavelength of light alongthe first optical path from the light emitting device and collimatingthe first wavelength of light to the second photodiode along the firstoptical path; and the second photodiode for reflecting the firstwavelength of light along the first optical path into the optical fiberalong a second optical path.
 14. Apparatus of claim 13, furthercomprising: the optical fiber for transmitting a second wavelength oflight to the second photodiode along the second optical path; and thesecond photodiode adapted and arranged to permit the second wavelengthof light to pass therethrough to the active region thereof forconversion into an electrical signal.
 15. Apparatus of claim 14, whereinthe first wavelength of light is different from the second wavelength oflight.
 16. Apparatus of claim 14, wherein the first optical path iscoincident to the second optical path.
 17. A method comprising steps of:providing an optical fiber; providing a bench that supports a chip-leveloptical transceiver; placing the bench in front of the optical fiber;activating the chip-level optical transceiver; and tilting the benchuntil the chip-level optical transceiver is aligned with the opticalfiber and an optical signal is achieved.
 18. The method of claim 17,further comprising mounting the optical fiber, the bench, and thechip-level optical transceiver carried by the bench in a package. 19.The method of claim 18, the package comprising: a support structuresecuring the fiber; a header coupled to the support structure; and thebench carried by the header in front of the optical fiber.
 20. Themethod of claim 17, wherein the chip-level optical transceivercomprises: a light emitting device, having an output, for emitting afirst wavelength of light along a first optical path; a first photodiodefor controlling the output of the light emitting device; a secondphotodiode having an active region; a lens for receiving the firstwavelength of light along the first optical path from the light emittingdevice and collimating the first wavelength of light to the secondphotodiode along the first optical path; and the second photodiode forreflecting the first wavelength of light along the first optical pathinto the optical fiber along a second optical path.